In some land-based turbine engines used in electrical power generating facilities, a plurality of combustors are arranged around the circumference of the turbine engine, and each of the combustors delivers hot combustion gases into the turbine section of the engine. The inlet to the turbine section is formed as an annulus that includes an inner annulus wall and an outer annulus wall. The outlets of the combustors are joined to the turbine inlet annulus. The outlet of each combustor is essentially rectangular shaped. However, the upper and lower sides of the outlet are arc-shaped such that when all of the combustors are arranged side-by-side around the exterior circumference of the turbine engine, the outlets of the combustors join to the circular shaped inlet annulus of the turbine section of the engine.
Circumferential seals are provided between the inner and outer annulus walls of the turbine inlet and the corresponding surfaces of the combustor outlets. In addition, side seals are located between the sides of each pair of adjacent combustors.
The outlet of each of the combustors and the turbine inlet annulus contain extremely hot combustion gases when the engine is operating. As a result, when a turbine is brought online, both the outlet portions of the combustors, and the elements of the turbine inlet annulus experience a large temperature swing. The thermal cycling between room temperature and the high temperatures that exist during normal operations can cause significant thermal expansions to occur. And because of the complex shapes of the individual elements which come together at the inlet annulus, the expansions can be non-uniform and unpredictable. As a result, it is common for small apertures to develop between the inlet annulus and the outlets of the combustors. One common location for such apertures to develop is at the corners of the combustor outlets, where the side seal between adjacent combustors meets the inner and outer circumferential seals. These apertures allow the hot combustion gases to leak. And this leakage of combustion gases represents an undesirable efficiency loss.